The recent remarkable development of television technology has been reflected in producing television receivers (hereinafter referred to as TV) which have a variety of additional functions. Furthermore, TVs may be used for displaying, besides usual TV broadcasts, a variety of other media such as satellite multichannel broadcast, CS broadcast, television game broadcast, music broadcast "karaoke" and so on. Such multi-function multi-channel TVs may be associated with complicated manipulation with an increased number of remote control buttons on a remote control unit. Many attempts have been made to improve the maneuverability of control means.
A television broadcast channel selecting device, which is one of basic functions of a television receiver, is now considered. A typical electronic tuner of the TV is used for selecting a broadcast channel by selecting a tuning voltage. The use of this electronic tuner enables a user to easily select a desired broadcast channel by pressing a corresponding channel selecting button on a remote control panel.
Sometimes the user wants to take a quick view of what current programs are broadcast at receivable channels on the TV screen to decide which program to enjoy. In this case, the user has to sequentially select channels by pressing a number of (e.g., ten) channel-selecting buttons on the control panel, recognizing a channel number every time before pressing the buttons. The provision of TV-channel selecting buttons "UP" and "DOWN" is also proposed, which method, however, can not directly select a desired channel and requires repeatedly pressing the button "UP" or "DOWN" until the desired channel number appears. It may take time and labor. Moreover both methods are limited to the number of channels to be selected.
Recently, there has been devised a channel selection aiding method by which a screen of a TV is temporally divided into a plurality of windows and still pictures of different TV broadcast channels are simultaneously displayed one in each window. This method may facilitate the selection of any desired program, but it involves a problem that an increasing number of receivable TV broadcast channels requires more divisions of the TV screen. This makes each window be smaller in area and be harder to recognize a picture displayed therein.
The above-mentioned techniques relate to TV tuners for selecting one of a plurality of receivable broadcast channels. Furthermore, the user of TVs may encounter in many circumstances the similar difficulty to select one from a large number of media or data.
Besides the foregoing remote control functions, selection of a particular one from a large number of things is also achieved by using a matrix switch which selects a particular button existing at one of cross points formed by rows and columns. This switch, however, has the limitation on the number of buttons and requires the user to accurately recognize a desired cross-point in the matrix.
The user interface of a computer terminal has hierarchically-ordered folders that can hold a number of files and can be opened downwards in the hierarchy to select a particular one of files. In this case, folders are successively presented in a two-dimensional plane on a TV monitor. With a large hierarchy containing a large number of folders, there may occur a problem that the screen of the monitor is crowded with the folders overlapping one another. This takes much times to open the folders and makes it harder to find a desired file.
Recently, another method has been proposed, which enables the user to access by means of a mouse to any one of many icons representing representative items in a pseudo-virtual space on a monitor screen to obtain lower-layer icons related to the accessed representative icons. The icons used thereon are difficult to distinguish from one another since they have similar shape with character expressions underneath. In order to promptly select a particular one of many representative icons disposed in the space, the user has to memorize the whereabouts of particular icons to be often selected. Furthermore, since the icons lack three-dimensional shape information, there is no possibility of distinguishing one another by utilizing the depth of space.
In addition, Japanese Laid-open Patent Publication Nos. 7-49764, 7-84746 and 7-114451 disclose methods of displaying icon menu, each of which uses a menu of three-dimensionally represented icons to help the user recognize and select a particular one of many icons. The presentation of icons in the depth in a three-dimensional space, however, is problematic in a that selectable icons may not easily be distinguished and selected. This is because icons disposed in the depth are smaller, and any system for indicating a particular place in the space is quite complicated to the user.
Namely, three-dimensional icons, as compared with conventional two-dimensional icons, are easier to recognize owing to their three-dimensional shape in the depth direction. However, the icons disposed in the depth of the space may be smaller, any place in the three-dimensional space may be frequently designated and it becomes difficult to determine icons which are selectable or to position a cursor on an area of a selectable icon by using a mouse.
The techniques disclosed in Japanese Laid-open Patent Publication Nos. 7-49764 and 7-114451 have common problems in that icons with names indicated underneath, which are arranged in an image of room space, are difficult to designate by a cursor and are too small to be easily distinguished, especially within the depth of the room space. It is difficult to correctly position a cursor over a particular one among a large number of such three-dimensional icons by using a conventional mouse. Consequently, both methods have a limitation on the size and the number of icons to be displayed.
The technique described in Japanese Laid-open Patent Publication No. 7-84746 requires the user to be skilled in manipulating a pointing device for rotating each cube side by side to select one of icons disposed on side surfaces of the cube. The selecting operation is completed. Furthermore, it is also difficult to find a desired icon because icons on surfaces of the cube have no linkage with each other.